title: Fracture resistance of premolar teeth restored with silorane-based or dimethacrylate-based composite resins.
abstract: BACKGROUND
  To restore posterior teeth using low-shrinkage composite to minimize microleakage.
  
  
  OBJECTIVE
  To compare the fracture resistance of mesio-occlusal-distal (MOD) cavity preparations restored with either low-shrinkage composite or with dimethacrylate-based composite in conjunction with cavity liners and without them. The null hypothesis of the study is that there are no differences in either fracture resistance or fracture mode between the silorane group and dimethacrylate groups with and without the use of cavity liners.
  
  
  METHODS
  Sixty maxillary premolars were divided into six groups of 10. MOD cavities were prepared in four groups: F: posterior composite (Filtek P60); GF: 0.5-mm Glass Ionomer (Fuji LC) + posterior composite; FF: 0.5-mm flowable composite (Filtek Supreme XT) + posterior composite; and S: low-shrinkage composite (Filtek P90). Negative (N) and positive (P) control groups consisted of unrestored and sound teeth, respectively. The specimens were thermocycled and loaded. Data were analyzed using analysis of variance, Tukey, and chi-square tests (α = 0.05).
  
  
  RESULTS
  Groups FF (1643.09 ± 187/80 N) and GF (1596.80 ± 163/93 N) (p = 0.06 > 0.05) were statistically identical, although less than group P (1742/33 ± 110/08 N), but still demonstrated greater fracture resistance than the other groups. The fracture resistance of group S (1434/69 ± 107/62 N) was identical to GF and FF (p = 0.06 > 0.05). The fracture resistance of F (1353/19 ± 233/90 N) was less than GF and FF, and statistically identical to S (p = 0.87 > 0.05).
  
  
  CONCLUSIONS
  Silorane-based composite showed a resistance to fracture similar to methacrylate-based composite restorations regardless of whether cavity liners were used.
  
  
  CONCLUSIONS
  The findings of this study support the selection of silorane-based composite for the restoration of maxillary premolars with standardized Class II cavity preparations in order to strengthen the resistance to fracture to the same extent as do dimethacrylate composites using cavity liners or without them.
authors.affiliation: Dental Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Golsa
authors.initials: G
authors.lastname: Akbarian
authors.forename: Hamideh
authors.initials: H
authors.lastname: Ameri
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Chasteen
authors.forename: Marjaneh
authors.initials: M
authors.lastname: Ghavamnasiri
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D003736:Dental Cavity Lining / Q000379:methods; D003737:Dental Cavity Preparation / Q000145:classification; D003763:Dental Leakage / Q000145:classification; D003764:Dental Materials / Q000737:chemistry*; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000145:classification*; D003799:Dental Stress Analysis / Q000295:instrumentation; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D008963:Molar / Q000503:physiopathology*; D019279:Resin Cements / Q000737:chemistry; D062047:Silorane Resins / Q000737:chemistry*; D013314:Stress, Mechanical; D013696:Temperature; D014082:Tooth Fractures / Q000503:physiopathology*
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C438835:Filtek P60 Composite Resin; C474035:Filtek Supreme; D005899:Glass Ionomer Cements; D008689:Methacrylates; D019279:Resin Cements; D062047:Silorane Resins; C544925:filtek P90; C115612:single bond; C084541:Fuji glass-ionomer lining cement; D017438:Bisphenol A-Glycidyl Methacrylate